Each email is slightly different, incorporating different reference numbers in the subject line, attached filename and message body. But the samples seen so far by Sophos all carry malware in the file "Adobe Systems Software Critical Update Dec 2011.exe" contained within the ZIP.

Computer users need to learn that Adobe never sends up software updates as an email attachment, and any legitimate upgrades should always be downloaded from Adobe's own website. It's trivial for a malicious hacker to forge an email header to trick the unwary into believing an email has been sent from someone else - so just because it claims to be from Adobe, doesn't mean that it was sent by them.